The US Navy has issued a navigational warning, instructing vessels in the Persian Gulf and Arabian Sea to keep a minimal 100-metre distance from US warships, otherwise they will be perceived as a threat.

Iran's navy will continue its regular missions in the Persian Gulf and the Sea of Oman despite a new US military directive warning of defensive measures if American warships are approached by armed vessels at a 100-metre radius, a senior military official told Iranian Students News Agency on Wednesday.

The directive in question was issued on Tuesday by the US Navy, which cited the necessity to enhance safety, minimise ambiguity and reduce opportunities for miscalculation due to "recent events".

Last month, President Donald Trump instructed the US Navy to destroy all Iranian gunboats that sailed too close to US warships. The order followed an incident in the Persian Gulf in which numerous patrol boats operated by Iran's Islamic Revolutionary Guard Corps sailed back and forth across the paths of several US vessels when they were engaging in drills just a few miles from Iranian waters. 

Iran condemned the move, saying that it undermined security in the region and warned the US against preparing any military moves.

Tensions between Washington and Tehran escalated further in early January and have been high ever since the Iranian top military commander, Soleimani, praised for combatting terrorist groups in the region, was killed in a targeted attack near Baghdad International Airport. In retaliation, Iran launched dozens of missiles at two US bases in Baghdad on 8 January, with over 100 US troops diagnosed with brain injuries of various severity as a result of the strikes.